# US 2021/0243816 A1 · Alternative modulation for a random access message in a two-step random access procedure > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2021/0243816 A1 - Document ID: US20210243816A1 - Status: Published application - Kind: A1 - Application number: 17/247,207 - Filed: 2020-12-03 - Published: 2021-08-05 - Earliest claimed: 2020-01-31 - Assignees: QUALCOMM Incorporated - Applicants: QUALCOMM Incorporated - Inventors: Mahmoud TAHERZADEH BOROUJENI; Juan MONTOJO; Tao LUO; Peter GAAL; Jelena DAMNJANOVIC - Web page: https://patentgrep.com/patent/US20210243816A1 ## CPC - H04L 43/16: Threshold monitoring - H04L 1/0003: {by switching between different modulation schemes} - H04L 1/0072: {Error control for data other than payload data, e.g. control data} - H04L 1/08: by repeating transmission, e.g. Verdan system {(H04L1/1858 and H04L1/189 take precedence)} - H04L 5/0048: {Allocation of pilot signals, i.e. of signals known to the receiver (allocation of control signalling H04L5/0053; use of control signalling H04L5/0091)} - H04L 27/18: Phase-modulated carrier systems, i.e. using phase-shift keying (H04L27/32 takes precedence) - H04L 27/20: Modulator circuits; Transmitter circuits - H04W 56/001: {Synchronization between nodes} - H04W 74/0836: with 2-step access - H04W 74/0833: Random access procedures, e.g. with 4-step access - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) ## Abstract Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may determine a set of modulations for a random access message associated with a two-step random access channel (RACH) procedure. The set of modulations may be either a first set of modulations or a second set of modulations that is different from the first set of modulations. The set of modulations may be determined based at least in part on whether a signal strength satisfies a signal strength threshold. The UE may transmit the random access message based at least in part on the determined set of modulations. The random access message may include a physical uplink shared channel modulated using the determined set of modulations. Numerous other aspects are provided. ## Claims ### Claim 1 A method of wireless communication performed by a user equipment (UE), comprising: determining a set of modulations for a random access message associated with a two-step random access channel (RACH) procedure, wherein the set of modulations is either a first set of modulations or a second set of modulations, the first set of modulations being different from the second set of modulations, and wherein the set of modulations is determined based at least in part on whether a signal strength satisfies a signal strength threshold; and transmitting the random access message based at least in part on the determined set of modulations, the random access message including a physical uplink shared channel (PUSCH) modulated using the determined set of modulations. ### Claim 2 (depends on 1) The method of claim 1, further comprising receiving system information from a base station, wherein the signal strength threshold is identified in the system information received by the UE. ### Claim 3 (depends on 1) The method of claim 1, further comprising receiving the signal strength threshold in system information comprising remaining minimum system information. ### Claim 4 (depends on 1) The method of claim 1, wherein determining the set of modulations comprises determining the set of modulations to be the first set of modulations when the signal strength satisfies the signal strength threshold and determining the set of modulations to be the second set of modulations when the signal strength does not satisfy the signal strength threshold. ### Claim 5 (depends on 4) The method of claim 4, wherein the second set of modulations is a π/2 binary phase shift keying scheme. ### Claim 6 (depends on 1) The method of claim 1, wherein transmitting the random access message comprises transmitting the random access message with an amount of time between a preamble of the random access message and the PUSCH, wherein the amount of time is based at least in part on the determined set of modulations. ### Claim 7 (depends on 6) The method of claim 6, wherein the preamble of the random access message is used for channel estimation enhancement of the PUSCH. ### Claim 8 (depends on 1) The method of claim 1, wherein transmitting the random access message comprises transmitting the random access message using a set of PUSCH resource unit groups, wherein the set of PUSCH resource unit groups when the first set of modulations is determined is different from the set of PUSCH resource unit groups when the second set of modulations is determined. ### Claim 9 (depends on 1) The method of claim 1, wherein transmitting the random access message comprises transmitting the random access message based on a set of RACH occasions, wherein the set of RACH occasions when the first set of modulations is determined is different from the set of RACH occasions when the second set of modulations is determined. ### Claim 10 (depends on 1) The method of claim 1, wherein transmitting the random access message comprises transmitting the random access message based on a mapping between a resource allocation for a PUSCH occasion and a RACH occasion, wherein the mapping when the first set of modulations is determined is different from the mapping when the second set of modulations is determined. ### Claim 11 (depends on 1) The method of claim 1, wherein transmitting the random access message comprises transmitting a payload of the random access message, wherein the payload when the first set of modulations is determined is different from the payload when the second set of modulations is determined. ### Claim 12 (depends on 1) The method of claim 1, wherein transmitting the random access message comprises transmitting a preamble for the random access message, wherein a length of the preamble when the first set of modulations is determined is different from the length of the preamble when the second set of modulations is determined. ### Claim 13 (depends on 1) The method of claim 1, wherein transmitting the random access message comprises applying preamble repetition for the random access message if the first set of modulations is determined and not applying preamble repetition if the second set of modulations is determined. ### Claim 14 (depends on 1) The method of claim 1, wherein transmitting the random access message comprises transmitting a preamble sequence, wherein the preamble sequence when the first set of modulations is determined is different from the preamble sequence when the second set of modulations is determined. ### Claim 15 (depends on 1) The method of claim 1, wherein transmitting the random access message comprises transmitting an indication of the determined set of modulations, wherein the indication is transmitted via at least one of a format of a preamble of the random access message, a length of the preamble, repetition of the preamble, a preamble sequence, or a set of resources in which the random access message is transmitted. ### Claim 16 (depends on 1) The method of claim 1, further comprising: receiving a synchronization signal block (SSB); and determining the signal strength based at least in part on a reference signal received power associated with the SSB. ### Claim 17 A method of wireless communication performed by a base station, comprising: receiving, from a user equipment (UE), a random access message associated with a two-step random access channel (RACH) procedure; determining, based at least in part on the random access message, a set of modulations associated with the random access message, wherein the set of modulations is either a first set of modulations or a second set of modulations, the first set of modulations being different from the second set of modulations; and processing the random access message based at least in part on the determined set of modulations associated with the random access message, the random access message including a physical uplink shared channel (PUSCH) modulated using the determined set of modulations. ### Claim 18 (depends on 17) The method of claim 17, further comprising transmitting system information that identifies a signal strength threshold associated with determining to use the second set of modulations. ### Claim 19 (depends on 17) The method of claim 17, wherein the second set of modulations is a π/2 binary phase shift keying scheme. ### Claim 20 (depends on 17) The method of claim 17, wherein receiving the random access message comprises receiving the random access message with an amount of time between a preamble of the random access message and the PUSCH, wherein the amount of time is based at least in part on the determined set of modulations. ### Claim 21 (depends on 17) The method of claim 17, wherein receiving the random access message comprises receiving the random access message using a set of PUSCH resource unit groups, wherein the set of PUSCH resource unit groups when the first set of modulations is determined is different from the set of PUSCH resource unit groups when the second set of modulations is determined. ### Claim 22 (depends on 17) The method of claim 17, wherein receiving the random access message comprises receiving the random access message based on a set of RACH occasions, wherein the set of RACH occasions when the first set of modulations is determined is different from the set of RACH occasions when the second set of modulations is determined. ### Claim 23 (depends on 17) The method of claim 17, wherein receiving the random access message comprises receiving the random access message based on a mapping between a resource allocation for a PUSCH occasion and a RACH occasion, wherein the mapping when the first set of modulations is determined is different from the mapping when the second set of modulations is determined. ### Claim 24 (depends on 17) The method of claim 17, wherein receiving the random access message comprises receiving a payload of the random access message, wherein the payload when the first set of modulations is determined is different from the payload when the second set of modulations is determined. ### Claim 25 (depends on 17) The method of claim 17, wherein receiving the random access message comprises receiving a preamble for the random access message, wherein a length of the preamble when the first set of modulations is determined is different from the length of the preamble when the second set of modulations is determined. ### Claim 26 (depends on 17) The method of claim 17, wherein receiving the random access message comprises applying preamble repetition for the random access message if the first set of modulations is determined and not applying preamble repetition if the second set of modulations is determined. ### Claim 27 (depends on 17) The method of claim 17, wherein receiving the random access message comprises receiving a preamble sequence, wherein the preamble sequence when the first set of modulations is determined is different from the preamble sequence when the second set of modulations is determined. ### Claim 28 (depends on 17) The method of claim 17, wherein determining the set of modulations comprises receiving an indication of the determined set of modulations, wherein the indication is received via at least one of a format of a preamble of the random access message, a length of the preamble, repetition of the preamble, a preamble sequence, or a set of resources in which the random access message is received. ### Claim 29 A user equipment (UE) for wireless communication, comprising: a memory; and one or more processors operatively coupled to the memory, the memory and the one or more processors configured to: determine a set of modulations for a random access message associated with a two-step random access channel (RACH) procedure, wherein the set of modulations is either a first set of modulations or a second set of modulations, the first set of modulations being different from the second set of modulations, and wherein the set of modulations is determined based at least in part on whether a signal strength satisfies a signal strength threshold; and transmit the random access message based at least in part on the determined set of modulations, the random access message including a physical uplink shared channel (PUSCH) modulated using the determined set of modulations. ### Claim 30 A base station for wireless communication, comprising: a memory; and one or more processors operatively coupled to the memory, the memory and the one or more processors configured to: receive, from a user equipment (UE), a random access message associated with a two-step random access channel (RACH) procedure; determine, based at least in part on the random access message, a set of modulations associated with the random access message, wherein the set of modulations is either a first set of modulations or a second set of modulations, the first set of modulations being different from the second set of modulations; and process the random access message based at least in part on the determined set of modulations associated with the random access message, the random access message including a physical uplink shared channel (PUSCH) modulated using the determined set of modulations.